Add handling for bind/unbind actions (#6720)

Add handling for bind/unbind actions (#6720)

Newer kernels will emit uevents with "bind" and "unbind" actions. These
uevents will be issued when driver is bound to or unbound from a device.
"Bind" events are helpful when device requires a firmware to operate
properly, and driver is unable to create a child device before firmware
is properly loaded.

For some reason systemd validates actions and drops the ones it does not
know, instead of passing them on through as old udev did, so we need to
explicitly teach it about them.